Is the use of a biomechanical device (INSJ) and spinal bone autograft (SPINAL BONE AUTOGRAFT) medically necessary for a patient with cervical spinal stenosis and intermittent numbness and tingling in the right arm, forearm, thumb, and index finger?

Medical Necessity Assessment for Biomechanical Device and Spinal Bone Autograft

Yes, both the biomechanical device (anterior cervical plating) and spinal bone autograft are medically necessary for this patient undergoing two-level ACDF at C5-C6 and C6-C7. The patient has failed prior decompression surgery, developed new radicular symptoms with documented moderate-to-severe neural foraminal stenosis and central canal stenosis, and requires multilevel fusion where autograft demonstrates superior outcomes.

Surgical Indication is Clearly Established

• The patient has progressive cervical radiculopathy with burning, tingling, and numbness in the right arm, forearm, thumb, and index finger that developed 3 weeks ago despite successful prior surgery 1
• CT imaging confirms at least moderate central canal stenosis at C6-C7 from posterior disc bulging and multilevel moderate-to-severe neural foraminal stenosis, most pronounced at bilateral C3-C4 and right-sided C6-C7 1
• Flexion-extension radiographs demonstrate slight instability at C5-C6, which is a clear indication for fusion rather than decompression alone 2
• The patient has failed conservative management and now requires surgical intervention for symptomatic stenosis causing radiculopathy 3

Biomechanical Device (Anterior Cervical Plating) is Medically Necessary

• Anterior plating is recommended for multilevel ACDF to reduce pseudarthrosis risk, maintain lordosis, and improve fusion rates, particularly important in two-level procedures like C5-C6 and C6-C7 4
• Stand-alone interbody cages without anterior plating demonstrate significantly higher range of motion in flexion-extension compared to plated constructs (P < 0.05), which can lead to fusion failure 5
• Biomechanical studies confirm that cervical interbody fusion cages should be supplemented with additional internal supports to prevent excessive motion in flexion-extension 5
• The patient has documented instability at C5-C6 on flexion-extension films, making anterior plate fixation essential for achieving solid arthrodesis 2

Spinal Bone Autograft is Medically Necessary for This Multilevel Procedure

• Autograft has demonstrated 100% fusion rates in multilevel cervical procedures compared to 89.5% for allograft, making it the superior choice for this two-level ACDF 1, 2
• The American Association of Neurological Surgeons recommends autograft bone harvested from the iliac crest as the gold standard for cervical fusion procedures due to its osteoinductive, osteoconductive, and osteogenic properties 1
• In multilevel procedures, autograft demonstrates significantly less subsidence (1.8 mm) compared to allograft (3.0 mm, p=0.005), which is critical for maintaining alignment and preventing hardware failure 2, 1
• Single-level autograft procedures achieve 97% fusion rates compared to 87% with allograft, and this difference becomes more pronounced in multilevel cases 2

Alternative to Iliac Crest Harvest: Local Autograft from Vertebral Body

• Vertebral autograft harvested during the corpectomy/discectomy can be used instead of iliac crest bone, avoiding donor site morbidity while maintaining the biological advantages of autograft 6
• A prospective study of 27 patients demonstrated 100% fusion rates using morselized vertebral body autograft packed into titanium cages during anterior cervical corpectomy 6
• This technique avoids complications associated with iliac crest harvest, which include a 2.8% reoperation rate, 5.6% superficial wound infection rate, and protracted pain in 2.8% of patients 7
• Vertebral autograft integrated well in cages and adjacent vertebral bodies with no evidence of morphological or functional instability when combined with anterior instrumentation 6

Critical Considerations for This Specific Case

• The patient is a 58-year-old male, which places him at higher risk for pseudarthrosis compared to younger patients, making the superior fusion rates of autograft particularly important 1
• Smoking status must be assessed, as smoking reduces fusion rates from 90% to 85% in single-level procedures and from 79% to 50% in two-level procedures with allograft 2
• The patient has already undergone posterior decompression (C3 laminectomy and C4 laminoplasty), making successful anterior fusion critical to avoid circumferential instability 2
• The presence of slight instability at C5-C6 on flexion-extension films makes rigid fixation with anterior plating and high fusion rates with autograft essential 2

Why Allograft Alone Would Be Inadequate

• Allograft fibula achieves only 89.5% fusion in multilevel procedures compared to 100% with autograft 2, 1
• Time to fusion is significantly delayed with allograft, with only 63.1% achieving radiographic fusion at 6 months compared to 89.2% with autograft 2
• Greater subsidence with allograft (3.0 mm vs 1.8 mm) increases the risk of loss of lordosis, foraminal height loss, and recurrent radiculopathy 2, 1
• The patient's documented instability at C5-C6 requires the most reliable fusion substrate available, which is autograft 1

Addressing Donor Site Morbidity Concerns

• If iliac crest harvest is planned, the patient should be counseled that major permanent morbidity occurs in only 0.7% of cases 7
• Female gender and obesity are risk factors for wound complications (5.6% infection/dehiscence rate), but this patient is male 7
• The preferred approach is to use local vertebral autograft from the discectomy sites, which eliminates donor site morbidity entirely while maintaining 100% fusion rates 6
• Local vertebral autograft can be morselized and packed into an interbody cage or used as structural graft, providing equivalent biological properties to iliac crest bone 6